Christian royal anointing takes its scriptural warrant from the Hebrew Bible, where Samuel anoints Saul and then David with oil at God's direction, and Solomon is anointed at Gihon in a ceremony the text treats as itself constituting his kingship, and Byzantine and Western Christian monarchies alike read these episodes as establishing a pattern rather than describing events belonging only to ancient Israel. The theological weight the rite carries follows directly from that borrowed vocabulary: anointing does not merely decorate a ruler already in office but is understood, in the traditions that practice it most solemnly, to change the ruler's spiritual status, setting the monarch apart, in some formulations quasi sacramentally, for an office regarded as answerable to God rather than granted by human election or inheritance alone.
Byzantine emperors, Western medieval kings and the rulers of Christian successor states across Europe adopted anointing with consecrated oil, usually chrism or a specially blessed oil, as the ceremonial core of coronation, distinct from and generally preceding the physical crowning itself, so that the crown, in the theology most coronations express, confirms a status the anointing has already conferred rather than creating it unaided.